title: Isolation prevalence of pulmonary nontuberculous mycobacteria in Ontario in 2007.
abstract: BACKGROUND
  The reported prevalence of pulmonary nontuberculous mycobacteria (NTM) infections is increasing.
  
  
  OBJECTIVE
  To determine the 'isolation prevalence' of NTM in 2007 and compare it with previously published research that examined the increasing rates of isolation of NTM from clinical pulmonary specimens between 1997 and 2003.
  
  
  METHODS
  Isolation prevalence was investigated retrospectively by reviewing a cohort of all positive pulmonary NTM culture results from the Tuberculosis and Mycobacteriology Laboratory, Public Health Laboratory (Toronto, Ontario) in 2007, which identifies at least 95% of NTM isolates in Ontario. Isolation prevalence was calculated as the number of persons with a pulmonary isolate in a calendar year divided by the contemporary population and expressed per 100,000 population. Changes in isolation prevalence from previous years were assessed for statistical significance using generalized linear models with a negative binomial distribution.
  
  
  RESULTS
  In 2007, 4160 pulmonary isolates of NTM were collected from 2463 patients. The isolation prevalence of all species (excluding Mycobacterium gordonae) was 19 per 100,000 population in 2007 - an increase from previous observations reported for Ontario - corresponding to an average annual increase of 8.5% from 1997 to 2007 (P<0.0001). Average annual increases in isolation prevalence of Mycobacterium avium complex (8.8%, P<0.0001) and Mycobacterium xenopi (7.3%, P=0.0005) were largely responsible for the overall increase, while prevalence rates of rapidly growing mycobacteria remained relatively stable.
  
  
  CONCLUSIONS
  The isolation prevalence of pulmonary NTM continues to increase significantly in Ontario, supporting the belief that pulmonary NTM disease is increasingly common.
authors.affiliation: University of Toronto, Toronto, Ontario.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Al Houqani
authors.forename: Frances
authors.initials: F
authors.lastname: Jamieson
authors.forename: Pamela
authors.initials: P
authors.lastname: Chedore
authors.forename: Mauli
authors.initials: M
authors.lastname: Mehta
authors.forename: Kevin
authors.initials: K
authors.lastname: May
authors.forename: Theodore K
authors.initials: TK
authors.lastname: Marras
mesh_terms: D006801:Humans; D008171:Lung Diseases / Q000453:epidemiology* / Q000382:microbiology; D009165:Mycobacterium Infections, Nontuberculous / Q000453:epidemiology*; D009170:Nontuberculous Mycobacteria / Q000302:isolation & purification*; D009864:Ontario / Q000453:epidemiology; D015995:Prevalence; D012189:Retrospective Studies